Phenotypic screening of extended-spectrum beta-lactamase producing Salmonella in retail shrimp

The occurrence of extended-spectrum beta-lactamase (ESBL) producing bacteria is concerning the scientific community since it confers multiple drug resistance (MDR). The study investigated the prevalence of MDR-ESBL-producing Salmonella strains from shrimp in, Bangladesh. A total of 165 shrimp samples were processed from 55 shrimp specimens from different retail shops. The presence of Salmonella was confirmed by standard methods followed by antibiotic susceptibility testing. Isolates exhibiting resistance to third-generation cephalosporin were considered as Salmonella positive isolates which was later proven by the double disc synergy test. Out of the total of 39 isolates tested, 18 were found to be Salmonella positive and originated from 7 departmental stores. The remaining 21 positive isolates were obtained from the local market. The body had the highest rate of positive samples (30.91%), followed by the head (23.63%), and the tail (16.36%). Additionally, isolated Salmonella were resistant to rifampicin and cefixime but 100% susceptible to co-trimoxazole, ofloxacin, streptomycin, nalidixic acid, and chloramphenicol, while ciprofloxacin showed intermediate resistance. Among the drugs tested, vancomycin, cephalexin, ampicillin, and colistin exhibited extreme resistance. Finally, while 6 of the tested isolates demonstrated resistance against the recommended cephalosporin, three of them (7.69%) were Salmonella ESBL positive in the double disc synergy test. In conclusion, the rising incidence of MDR and the developing prevalence of ESBL-positive Salmonella may put a burden on the healthcare system by limiting access to effective antibacterial drugs.